EFFECT OF DIRECT SUNLIGHT AND UV-RAYS ON DEGRADATION OF BUPIRIMATE, PENCONAZOLE AND PROFENOFOS

The exposure to sunlight, UV-rays led to the degradation of the pesticides formulations (Namrod 25% EC) bupirimate, (Agrozole 10% EC) penconazole and (Actacron 72% EC) profenofos. Their residues were determined by high performance liquid chromatography (HPLC). The results showed that exposure to direct sunlight in (Winter at the morning) was more effective in degradation of the tested pesticides than exposure to direct sunlight in (Winter at the evening) for 4 hours. The percentage residue of bupirimate, penconazole and profenofos were 18.24, 48.52 and 19.26 % in winter at the morning, respectively. Therefore, bupirimate was the highest affected by this treatment. Also, the data showed that exposure to direct sunlight in (Summer at the evening) was more degraded than exposure to direct sunlight in (Summer at the morning) for 4 hours. The percentage residue of bupirimate, penconazole and profenofos were 11.14, 15.45 and 7.72 % after 4 hours in (Summer at the evening), respectively. Therefore profenofos was more degraded than other pesticides. In general the degradation of the tested pesticides in summer was higher than winter. Withal, the data demonstrated that the exposure to UV-ray at distance 22.5 cm was more effective in degradation of the three tested pesticides than exposure to UV-ray at distance 45 cm for 4 hours where, the percentage residue of bupirimate, penconazole and profenofos were 17.08, 39.56 and 15.00 % after 4 hours of exposure to UV-ray at distance 22.5 cm respectively, and therefore profenofos was the highest degraded in the three pesticide in the same period of exposure to UV-ray.